Cucumber examples depending on slow response

I’ve got some scenarios where we want to make sure that the ‘delay indicator’ (the little spinner) is actually displayed if there are delays in the backend or the network.

These are all manual scenarios (no automation here :=) but it’s still problematic as sometimes the application responds too quickly and the spinner doesn’t have a chance to display.

Is there an app I can load on the iPhone or Android device to just suck up CPU cycles and make things slow or is there some other way to test this stuff?